<!DOCTYPE html>
<html>
<head lang="en">
    <meta charset="UTF-8">
    <title></title>
    <style>
        .outer{
            width: 100%;
            background-color: red;
        }
        .label{
            width: 10px;
            /*background-color: blue;*/
        }
        .name{
            width: calc(100% - 10px);
            background-color: yellow;
            ;
        }
    </style>
</head>
<body>
        <div class="outer">
            <label class="label" for="name">label</label> <span class="name">123</span>
        </div>
</body>
</html>